The Japanese Navy first established P Base at Ōurasaki for midget submarine
training. The Navy in 1944 set up a second training base, named Q Base, on the
eastern end of Kurahashi Island at Ōsako. This base was located only about six
kilometers from P Base.

The stone monument at the former Q base site has the following engraved on
front: Special Submarine Base Ōura Totsugeki Unit Ōsako Detachment Monument. A
"special submarine" (tokushu senkōtei in Japanese) is commonly referred
to as a midget submarine in English. No date is given as to when the monument
was erected.

The stone plaque to the right of the monument, donated by Kaneto Origuchi of
the Special Submarine Association, provides the following history:

In April 1944 during the height of the Greater East Asia War as enemy
counterattacks rapidly became more fierce, the Navy established a secret
training base here. In concert with Ōurasaki Special Submarine P Base on the
opposite shore, it was called Q Base.

In July 1944, the 1st Special Base Unit was formed, and the men at the
base were under this command. In March 1945, its name was changed to the
Ōura Totsugeki Unit Ōsako Detachment. Two thousand patriotic officers and
men ready to die for their country gathered here at this cool and clear
place with blue waters.

These men, all loyal warriors willing to die, received training in combat skills to
kill the enemy and faced both the north wind and the sweltering heat. Many
of these young cherry blossoms made sortiesin high spirits.

But in August of the same year we received the imperial edict ending the
war, and the unit was disbanded in an orderly fashion. After more than 50
years have passed, we remember those days and engrave this monument to tell
our posterity.